1. Technical Field
The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a phase change memory device and a method of manufacturing the same.
2. Description of the Related Art
As an integration degree of a semiconductor increases, patterns forming a circuit are miniaturized and a gap between adjacent patterns is decreasing. To form contact holes in a smaller size, double patterning may be used.
For example, in the double patterning process, photoresist patterns are formed by performing photolithography twice between photoresist patterns at a pitch of photolithographic resolution restrictions. Thus, contact holes or patterns at a pitch not exceeding photolithographic resolution restrictions can be formed using double patterning.
A phase change random access memory (PRAM) is a device that stores data using a phase change material making transitions between amorphous and crystalline states when it is cooled after being heated. A PRAM generally includes diodes, a lower electrode and a phase change material. To fabricate a PRAM having fine patterns, double patterning may be performed when forming the diodes, the lower electrode and the phase change material, respectively.
However, conventional double patterning processes involve two photolithography processes, which may require high-priced equipment and application of a complex sequence of processes. Therefore, fabricating a PRAM with fine patterns by performing multiple double patterning processes may increase the manufacturing cost and process time.
Accordingly, there is a need for manufacturing a PRAM with fine patterns while performing a minimum number of double patterning processes.